Western Regional Research Center, Healthy Processed Foods Research, 800 Buchanan St., Albany, CA, 94710, U.S.A.
Department of Food Science and Technology, Univ. of California, Davis, Davis, CA, 95616, U.S.A.
J Food Sci. 2019 Mar;84(3):412-420. doi: 10.1111/1750-3841.14447. Epub 2019 Feb 7.
This study investigated drum-drying's ability to produce dried food-grade olive pomace as a potential food ingredient that is more nutritionally dense than its freeze-dried and hot-air dried counterparts. The pits and skin were removed from fresh olive pomace, and the remaining pulp was dried to <5% moisture through freeze-drying, hot-air drying, and drum-drying at two rotational speeds. The drying treatments had no significant (P ≤ 0.05) effect on the olive pomace's fat or dietary fiber contents but did increase the L , a , and b color parameter values. Although all the drying treatments significantly (P ≤ 0.05) decreased the fresh olive pomace's antioxidant capacity, drum-drying preserved the olive pomace's antioxidant capacity significantly (P ≤ 0.05) better than freeze-drying and hot-air drying. The drum-dried samples had concentrations of caffeic acid and verbascoside that were significantly (P ≤ 0.05) higher than the other dried pomace samples and were not significantly (P ≤ 0.05) different from the fresh pomace. The drum-dried olive pomace contained concentrations of hydroxytyrosol, tyrosol, vanillic acid, luteolin-7-glucoside, and rutin that were not significantly (P ≤ 0.05) different from the dried sample with the highest concentration of each respective phenolic compound. No oleuropein was found in the fresh or dried olive pomace. The results of this study show that drum-drying is an energy efficient method for converting olive pomace into a stable food-grade supplement that preserves its high phenolic, antioxidant, and dietary fiber contents to potentially benefit human health when incorporated into food or supplement products. PRACTICAL APPLICATION: Pitting and drying converts the olive pomace into a stable form that is free of physical hazards and could be incorporated into food products to increase their nutritional quality through olive pomaces' high fiber, antioxidant, and phenolic contents. Drum-drying allows food-grade olive pomace to retain higher amounts of beneficial soluble phenolics and a higher antioxidant capacity than conventional drying methods, thus furthering olive pomace's potential valorization as a food ingredient.
本研究考察了鼓式干燥对生产干食级橄榄渣的能力，橄榄渣作为一种潜在的食品成分，其营养价值高于冷冻干燥和热空气干燥的对应物。从新鲜橄榄渣中去除核和皮，将剩余的果肉通过冷冻干燥、热空气干燥和在两种转速下的鼓式干燥干燥至<5%的水分。干燥处理对橄榄渣的脂肪或膳食纤维含量没有显著影响（P≤0.05），但确实增加了 L、a 和 b 颜色参数值。虽然所有干燥处理都显著降低了新鲜橄榄渣的抗氧化能力（P≤0.05），但鼓式干燥对橄榄渣抗氧化能力的保护显著优于冷冻干燥和热空气干燥（P≤0.05）。鼓式干燥样品中咖啡酸和毛蕊花糖苷的浓度显著高于其他干燥的橄榄渣样品（P≤0.05），与新鲜橄榄渣没有显著差异（P≤0.05）。鼓式干燥的橄榄渣中羟基酪醇、酪醇、香草酸、木樨草素-7-葡萄糖苷和芦丁的浓度与各酚类化合物浓度最高的干燥样品没有显著差异（P≤0.05）。新鲜或干燥的橄榄渣中均未发现橄榄苦苷。本研究结果表明，鼓式干燥是将橄榄渣转化为稳定的食级补充剂的一种节能方法，可在将其添加到食品或补充剂产品中时，保持其高酚类、抗氧化和膳食纤维含量，从而可能有益于人类健康。实际应用：去核和干燥将橄榄渣转化为稳定的形式，无物理危害，可以将其掺入食品产品中，通过橄榄渣的高纤维、抗氧化和酚类含量来提高其营养价值。鼓式干燥可使食级橄榄渣保留比传统干燥方法更多的有益可溶性酚类和更高的抗氧化能力，从而进一步提高橄榄渣作为食品成分的潜在价值。
